Draft gear train action control valve



Aug. 26, 1969 w. T. BLAKE 3,463,328

DRAFT GEAR TRAIN ACTION CONTROL VALVE ATTORNEY:

w. T. BLAKE 3,463,328

DRAFT GEAR TRAIN ACTION CONTROL VALVE 3 Sheets-Sheet 2 Aug. 26, 1969 Filed Jan. 2e, 1967 Aus- 26, 1969 w. T. BLAKE 3,463,328

DRAFT GEAR TRAIN ACTION CONTROL VALVE Filed Jan. 26. 1967 3 Sheets-Sheet 3 FIG? INVENTOR WILLIAM T. BLAKE By M, Dam, ma, M fw ATTORNEYS' United States Patent O U.S. Cl. 213-43 2 Claims ABSTRACT OF THE DISCLOSURE A valve apparatus for inclusion in railway draft gear of the type which includes a fluid shock absorbing assembly comprising cylinder means and piston means. The valve means is disposed to regulate an outow of lluid from a piston biasing iluid zone of the assembly. In the context of this draft gear, the valve is characterized by port means carried by a movable valve member. This port means causes the movable valve member to be closable in response to fluid flow therethrough emanating from the piston biasing zone of the assembly. Resilient means tend to bias the movable valve member to an open port position.

BACKGROUND OF INVENTION In recent years, considerable'attention has been paid to the development of hydraulic shock absorbing mechanisms to cushion forces imposed on railway car couplings. i

A primary function of these shock absorbing mechanisms is to absorb the exceedingly high buff forces which are often imposed on couplings during the intercoupling of railway cars in railway yards.

Particularly effective railway shock absorbing mechanisms are described in Blake Patent 2,944,639 and in the Seay Patent 3,301,410.

In certain railway systems, such as some in Canada, extremely adverse track conditionsvare encountered which tend to induce an extraordinarily high degree of train action. Train action is a term applied to phenomena which occur as a consequence of slack in the couplings between railway cars, which slack enables cars to undergo relative movement while a train is in motion. Specifically, train action denotes the equalizing of speed of adjacent cars which have undergone relative movement. Where this relative movement is characterized by the adjacent cars moving apart, this action is termed run-out. Where adjacent cars are tending to converge, this train action is referred to as a run-in.

Such run-out and run-in phenomena produces a variety of undesirable effects. 'For example, during the period while couplings are extending or contracting, train crewmen have reported that they experience a floating sensation. Once couplings have ceased their extension or contraction, train action shocks of a high magnitude `are imposed on cars which are noticeably severe and occasionally severe enough to jolt and injure crewmen. Such train action shocks also obviously are injurious to train components and may produce derailment tendencies.

The magnitude of the train action problem is discussed in connection with experimental and evaluation efforts pertaining to Canadian railway systems in a paper authored by F. E. King and R. W. Radford, entitled The Effect of Freight Car Cushioning Characteristics on Train Action, and presented at the winter annual meeting of the American Society of Mechanical Engineers held in New York in November and December of 1966. Some appreciation of the track profile conditions which produce excessive train action may be gathered by reference to this article.

Coping with the train action phenomena `presents reice quirements which are not aligned with those involved in maintaining the desired characteristics of coupling bars while they are not being subjected to heavy, extraneous forces. For example, in order to restore at a satisfactory fast rate from a full buff condition, hydraulic shock absorbing mechanisms are necessarily characterized by relatively high capacity restricted passage means for venting fluid from coupler bar, movement resisting, fluid bodies. However, in order to effectively limit coupling movement while trains are in motion where coupling forces of a considerable lower magnitude are generally involved, it is necessary to provide a more restricted venting of fluid from such fluid bodies.

SUMMARY OF INVENTION An overall apparatus and technique for effectively controlling and minimizing train action events without adversely interfering with the shock absorbing capability of railway draft gear is described in an application of Jack G. Stephenson and Robert E. Abbott entitled Draft Gear Train Action Control System, Ser. No. 610,553, filed Jan. 20, 1967. In the context of this overall apparatus and technique, it is a principal object of the present invention to provide a valve mechanism which affords effective control over train actionI run-out events, i.e., tendencies of a coupling bar to extend while a train is in motion.

It is another principal object of the invention to provide a valve apparatus for enabling railway car shock absorbing devices to minimize train action run-out events while at the same time permitting such devices to restore at a satisfactory rate from a full buff position to a neutral position when not subjected to train action forces.

A further object of the invention is to provide a valve apparatus for effectively controlling train action run-out phenomena without requiring drastic alteration of existing shock absorbing mechanisms such as those described in the aforesaid Blake patent and Seay application.

It is a related object of the invention to provide -such an improved valve structure which is compact, structurally rugged, and readily incorporated in` existing railway draft gear.

Yet another object of the invention is to provide such an improved valve structure which is positive in its valve closing and opening action and which is positively protected against undesired valve chattering tendencies.

A still further object of the invention is to provide such an improved valve apparatus which is operable in response to a flow of fluid from a piston biasing zone of hydraulic draft gear, with the valve being biased to a normally open position and closable in response to such a flow generated by train action forces acting upon a coupling bar.

In accomplishing these objects, there is provided an improved valve mechanism which is integrally incorporated in railway draft gear of the type which includes a iluid shock absorbing assembly comprising cylinder means and piston means. In this apparatus setting for the improved valve mechanism, the piston means is connected with one of a coupling portion and body portion of a railway car and the cylinder means is `connected with the other of these coupling and body portions. The valve means, in this context, serves to regulate an outflow of fluid from a piston biasing zone of the assembly.

The improved valve means includes a valve body, a movable valve member, and a valve seat carried by the valve body. Port means carried by the movable valve member serves, in response to a fluid ow therethrough emanating from the piston biasing zone of the assembly, to create a pressure differential across the movable member tending to move the movable valve member into port means closing engagement with the valve seat. A resilient means biases the valve member away from the valve seat so as to yieldably position the valve member with its ports open.

In the context of this improved valve arrangement, an additionally and independently significant combination involves this improved valve structure in combination with a fluid reaction surface on the movable valve member upon which uid outflow from the assembly is adapted to impinge and apply a valve closing reaction force.

A further independently significant combination involves the improved valve arrangement as above described in further combination with dashpot means, i.e., movement retarding means, which tend to retard movement of the valve member toward the valve seat.

DESCRIPTION OF DRAWINGS In describing the invention, reference will be made to the preferred embodiment of the apparatus illustrated in the appended drawings.

In the drawings:

FIGURE 1 provides an elevational prole of a portion of a test track over which trains were run in order to evaluate the improved ability of the cushioning or shock absorbing mechanism of the present invention to minimize train action events and reduce their severity;

FIGURE 2 provides a graphical comparison of the performance of railway cushioning gear constructed gener-al accordance with the present invention as opposed to the performance of conventional, friction-type, draft gear;

FIGURE 3 provides a partially sectioned, elevational view of a shock absorbing mechanism of the present invention in the format of an improvement in the mechanism disclosed in the aforesaid Seay application, Ser. No. 527,347;

FIGURE 4 provides an enlarged transverse sectional view of a portion of the FIGURE 3 mechanism illustrating structural details of a valve controlled vent, as viewed along the section line 4-4 of IFIGURE 3;

FIGURE 5 provides a still further enlarged transverse sectional view of the valve mechanism shown in FIG- URE 4 as viewed along the section line 5-5 of FIG- URE 4;

FIGURE 6 provides an enlarged elevational view of the valve shown in FIGURE 5;

FIGURE 7 provides an end view of the FIGURE 6 valve as viewed along the view direction 7-7; and

FIGURE 8 provides a transverse sectional view of the ow restricting ports included in a valve member of the FIGURE 6 valve assembly.

OVERALL APPARATUS FIGURES 3 through 8 illustrate structural details of a railway cushioning device fabricated in accordance with the present invention.

FIGURE 3 illustrates an improved form of the cushioning device illustrated and described in detail in the aforesaid Seay Patent No. 3,301,410. Brieliy reviewing the structural characteristics of this cushioning device 1, without unnecessarily redescribing structure which is known in the art, it will be appreciated that the basic components of this device 1 comprise a housing 2 having a generally rectangular cross section, a high pressure cylinder 3 contained within housing 2 and having a cylindrical cross section, a piston 4 mounted for telescoping movement within the cylinder 3, and an anchor Iassembly 5. A conventinal coupling bar 6, shown in phantom lines in FIGURE 3, is adapted to be connected by conventional mounting keys or a pivot pin to housing 2.

Housing 2 is adapted to be movably mounted, i.e., slidably mounted in a sill beneath a railway car body, with anchor assembly 5 being fixedly anchored to a sill portion. In this manner, anchor assembly 5, which is connected to a piston rod 7 extending from and connected with piston 4, serves to tixedly position the piston 4 within a railway car sill.

Cylinder end walls 8 and 9 are secured to opposite ends of cylinder wall 3 so as to define a high pressure cavity 10 within cylinder 3 and a relatively low pressure zone 11 encircling cylinder 3 and disposed between the housing 2 and the cylinder 3. This Zone 11 communicates through openings in end walls 8 and 9, not shown, with check valve means 12 and 13 contained in walls 8 and 9 respectively. This general check valve and passage arrangement is fully described in the aforesaid Blake Patent 2,944,681 and Seay Patent No. 3,301,410, and for that reason, need not be reillustrated.

As described in this Blake patent, and Seay application, the low pressure zone surrounding the cylinder wall 3 and end walls 8 and 9 is sealed at opposite ends of the housing 2. Thus, as shown in FIGURE 3, the left end of this low pressure zone is sealed by annular seal means 14 interposed between housing 2 and a housing end plate 15.

'Piston rod 7 telescopingly passes through the end plate 15 and is in sealed but slidable engagement with this plate. An axially extendable and contractable seal 16, connected to the end plate 15 and a piston rod portion 17, serves to protect the portion of the piston rod 7 which passes slidably through the housing end plate 15.

A coil spring restoring mechanism 18, preferably of the types disclosed in the U.S. Blake Patent 3,047,162 or in U.S. Abbott et al. Patent 3,233,747 led Jan. 22, 1964, is incorporated in device 1. This restoring mechanism |18 tends to resiliently and yieldably maintain the housing 2 within a railway car sill in a predetermined neutral position so as to obtain a desired `position of the piston 4 within the cylinder 3 when the coupling bar 6 is separated from the coupling of an adjacent railway car. In this connection, it will be understood that in FIGURE 3, the piston 4 is illustrated in a position where it has been displaced from its usual neutral position in response to the application of buff force to the coupling bar 6. In the FIGURE 3 arrangement, it is contemplated that the restoring mechanism `18 would ordinarily tend to position the piston 4 so that a split piston ring 19 having a ring split or gap I19a is carried by the piston 4 will have its draft or right edge 19b substantially aligned with the plane P. This use of this ring provides an improved seal between the piston 4 and cylinder 3 and thus represents an improvement over the devices of the aforesaid Seay application and Blake patents.

Port means 20, comprising a plurality of radial ports spaced longitudinally of the cylinder wall 3 and extending through the cylinder wall 3, provide tluid communication between the zones 10 and 11.

Key slots 21 and 22 may be provided in housing 2 to receive conventional cushioning device mounting keys of the type described, for example, in Blake Patent 3,207,324 and Blake Patent 3,047,162. These mounting keys extend fairly snugly through the slots 21 and 22 and into relatively long, longitudinally extending sill slots. The length of the sill slots may serve to determine the stroke of the cylinder 3 relative to the fixed piston 4 and thus limit the stroke in both bul and draft directions. That is, when the mounting keys engage either end of a sill slot, further movement of the cylinder 3, housing 2, and coupling bar 6 is prevented. In some instances, a housing ange carried `by the housing 6, as shown for example at element 65 in the Blake Patent 3,207,324, may abuttingly engage the sill end in response to imposition of buff force so as to delineate the termination of buff movement of the housing 2, cylinder 3, and coupling bar 6.

The basic mode of operation of the previously described components of the FIGURE 3 assembly is described in considerable detail in the aforesaid 'Blake patents, Abbott et al. patent and Seay application.

In brief review, when buff forces are imposed on the coupling bar 6 with the piston 4 disposed at its neutral position, fluid will be'displaced from an annular zone 10a to the left of the piston buff end 4a through the port -means into the zone 11. This displaced lluid will travel from the zone 11 through the previously described openings in the plate 9 to pass through the check valve means 13 into the zone 10b to the right of the piston 4. The port means 20, in restricting flow from the zone 10a, will cause the fluid within the zone 10a to absorb buff forces and thus cushion the imposition of buff shock on a railway car.

Conversely, when draft force is `applied to the coupling bar 6 with the piston 4 disposed as shown in FIGURE 3, fluid will be displaced by the piston draft end 4b from the annular zon-e v10b through the port means 20. This displaced fluid will flow through the previously described openings in the end plate 8 and return to the annular zone 10a through the check valve means 12. As will be appreciated, check valve means 12 and 13 are biased to a closed position by conventional coil spring mounting arrangements and open inwardly into the zones 10a and 10b in response to a pressure differential across them characterized by a low pressure zone adjacent the check valves within the cylinder cavity 10.

IMPROVED PORTING AND PISTON ARRANGEMENT The FIGURE 3 assembly is characterized -by an improved arrangement of venting ports and piston-components which provide effective control over train action events without impairing the ability of the FIGURE 3 assembly to absorb heavy buff impact under coupling conditions.

This improved porting arrangement is characterized by a first plurality of longitudinally spaced, cylinder wall ports 23. Ports 23 are exponentially spaced and progressively and exponentially decrease in spacing in a longitudinal direction extending toward the coupling bar 6. In order to obtain the desired orifice coefficient characteristics of these flow-restricting ports, the dimensional relationships in the aforesaid Seay application should be followed. That is, the port diameters should fall within a range of about .28 inch to about .38 inch. In practice a diameter of 5/16 of an inch for each port 23 has been found to produce satisfactory results, consistent with the teaching of this Seay application.

A second plurality of venting ports 24, longitudinally displaced from the first plurality of ports 23, is disposed between the ports 23 and the coupling bar 6. Ports 24 lare preferably also dimensioned in accordance with the teachings of the aforesaid Seay application and in practice, have been found to perform satisfactorily when having a diameter of about /16 of an inch. However, the ports 24, rather than being exponentially spaced, are equally spaced.

In a tested embodiment where the piston 4 had a diameter of about 9 inches and where the relative travel of piston 4 within cylinder 3 is about l0 inches, i.e., when housing 2 and cylinder 3 have a full stroke of l() inches, satisfactory results have been obtained with six ports in the port means 23 and three port means in the port means 24, with all of these ports being 5A6 of an inch in diameter.

As will be appreciated, the ports 23 and 24 are disposed to the left of the piston 4 when it has assumed its neutral position, as determined by the spring mechanism 18. Thus exponentially spaced ports 23 and uniformly spaced ports 24 serve to control fluid flow from the cylinder cavity 10 during the imposition of buff force when the cylinder is moved from its neutral position.

As shown in FIGURE 3, the cylinder 3 has been moved so as to position the piston 4 at the end of its buff stroke. In this position, the leftmost port 24a is displaced from the leftmost end 4a of the piston 4 by a distance of .75 inch. With these dimensional relationships, the longitudinal width of the piston 4 has been gauged at about 21/2 inches with the ring 19 having a width of about .37S inch and being spaced from the left or lbuff end 4a of the piston 4 a distance of 1.22 inches.

Although the split piston ring 19 provides slidable and Sealing engagement radially between the piston 4 and cylinder 3, some limited and throttled fluid flow between the cylinder and piston may take place through the ring split zone 19a. Thus, when the piston 4 has been positioned so as to cover the leftmost port 24a, continued, but highly resisted, piston movement relative to cylinder 3 may continue, with fluid venting from zone 10a through ring split 19a into zone 10b'. As will be further noted, when coupling 6 has moved to its full buff position so as to position piston 4 as shown in FIGURE 3, the port means 24 will have been covered.

It will also be appreciated that after the left edge 4a of the piston 4 has covered the port 24a, some limited and throttled leakage may take place between the piston 4 and cylinder 3 to the left of ring 19 as shown in FIG- URE 3, thereby enabling iluid to ilow from the zone 10a into one or more of the ports 24. However, it is believed that the combined ilow capacity of this leakage, as well as the leakage through ring split zone 19a, is not as great as the flow capacity of individual port 24. Thus, when the cylinder 3 has |moved sufficiently to cause the piston 4 to cover the ports 24, further buff movement of the cylinder 23 will take place with intensified or increased resistance.

With the buff controlling port means 23 and 24 having been described, it now becomes appropriate to describe the draft controlling port means of the FIGURE 3 apparatus.

It should be here observed, that in the FIGURE 3 embodiment, the cylinder 3 may travel nine inches from its neutral position in response to the imposition of buff force and one inch from its neutral position in response to the imposition of draft force.

This draft controlling port means comprises, in the right or draft end of the cylinder wall 3, a relatively restricted single port 25 and a valved port 26. As illustrated, restricted port 25 is longitudinally interposed between valve port 26 and first port means 23. Thus, restricted port 25 may be viewed as third vent means with valve port 26 being viewed as fourth vent means.

At this point, it yshould be observed that in indicating that various ports of the port or vent means are longitudinally displaced, what is meant is that the ports are aligned with planes perpendicular to the longitudinal axis of the assembly 1, with these planes being longitudinally displaced.

Longitudinal spacing, as previously u-sed in this discussion, and as used subsequently, is intended to encompass not only longitudinal spacing with the maintenance of axial port alignment, but also longitudinal displacement where ports are circumferentially displaced from each other. Indeed, in practice, it has been found that it is undesirable to longitudinally align all of the venting ports of the apparatus. Because of the extreme fluid pressures encountered within the cavity 10, metal deformation in the vicinity of the venting ports may tend to result. Where all of the ports are aligned, this axial alignment of deformed areas may tend to produce an undesired interference action between the piston and cylinder.

As shown in FIGURE 3, valved port 26 is preferably aligned with plane lP, i.e., the location of the draft or right edge 19h of the piston ring 19 when the piston 4 is in its full draft position. Thus, with the valved port 26 open, even though a portion of the piston 4 covers the port 26, fluid may llow from the zone 10b, to the left as shown in FIGURE 3 and between the piston 4 and cylinder wall 3, and then through the port 26 into the 10W pressure zone 11. This zone outflow, coupled with the by-pass outflows from the zone 10b through the ring split 19h to the zone 10a, will enable a desired rapidity of cylinder movement near the end of a draft stroke under conditions where the valve port 26 remains open. This restoration rapidity is desirable under free air conditions-ie., when coupling bar 6 is disconnected from an adjacent car.

In practice, it has been found desirable for the longitudinal distance between the centerline of the port 26 and the right or draft end 4b of the piston 4 at its full draft position to be on the order of 1.77 inches. Similarly, it has been found acceptable for the distance from this draft edge 4b of the piston 4 in its full draft position to the center line of the port 25 to be on the order of about 2.37 inches, with port 25 having a diameter of about 1/10 of an inch.

For a more detailed treatment of the location of port means 23, 24, 25 and 26 in cylinder 3, the criteria for locating these parts, and the overall mode of operation of draft gear 1, reference should be made to the aforesaid Stephenson application.

A valve mechanism 27 is mounted on the exterior of cylinder wall 3 and cooperates with cylinder wall 3 and port 26 to define a valved, radial flow path extending from cylinder cavity 10. This flow path is unique in that the valve mechanism 27 is resiliently biased to an open position and tends to remain open until a predetermined pressure is created within cylinder draft zone b in response to the imposition of a predetermined draft force on coupling bar 6. This predetermined force is of such a level as to be higher than the force imposed on housing 2 by restoring 'mechanism 18 but at least equal to the normal level of forces imposed on the coupling 6 as a consequence of run-out train action. As a consequence, port 26 will remain open while the coupling 6 is restoring from a full buff condition as shown in FIGURE 3, with the coupling 6 'being disconnected from an adjacent railway car. However, the port 26 will be valved closed in response to the imposition of run-out forces on the coupling `6 while it is connected to the adjacent car of a train in motion.

VALVE STRUCTURE Structural details of valve mechanism 27 are illustrated in FIGURES 4 through 8.

Mechanism 27 includes a generally cylindrical body portion 28 and a reduced threaded coupling portion 29 which is threadably secured in a threaded socket portion 30 of cylinder wall 3. With body 28 thus threadably secured to threaded socket 30, the longitudinal axis of the valve 27 projects generally radially into a corner portion 11a of cavity 11. In other words, valve 27 projects generally radially toward rectangular housing corner 2a so as to project into a portion of the reservoir 11a large enough to accommodate the valve body without requiring enlargement of the housing 2.

Valve 27 includes a tubular and movable valve member 31 which is telescopingly received with a valve body opening 32. Movable valve member 31 is provided at the end facing port 26 with a head 33 providing a fluid reaction surface 34. This surface 34 extends generally transversely of the radial axis of port 26 and faces this port. A pair of diametrically opposed, restricted, radial ports 35 intersect the tubular wall of valve member 31 adjacent the valve member head 33.

In practice, it has been found that the diameter of the head 33 should be on the order of .65 inch with the two ports 35 each having a diameter of about 2%() of an inch. Each of the ports 3S communicates with a longitudinal passage 37 of tubular member 31 which has been found to have a satisfactory diameter of V16 inch, i.e., the same diameter as port 26. Thus, passage 37 provides fluid communication, through ports 35, between port 26 and reservoir 11.

An annular under lip or abutment 38 on the head 33 of valve member 31 is adapted to abuttingly engage an annular, abutment defining upper end 39 of valve body portion 29 so as to limit radial outward movement of the valve member 31. With the valve member 31 being telescoped radially outwardly of the valve body 28 so as to bring the abutments 38 and 39 into engagement, the ports 35 will have been brought into port closing engagement with tubular valve seat 40 defined by the cylindrical wall encircling opening 32.

An annular piston 41 is slidably and telescopingly positioned within valve body portion 28. Annular piston 40 includes a central aperture 42 through which valve member 31 projects. Annular piston 41 engages an annular shoulder or abutment 43 on valve member 31 and is secured against this` abutment by a conventional snap ring 44 which is secured within an annular recess 45 of member 31.

A coil spring 46 abuttingly engages annular piston 41 and is secured within the housing portion 28 by an annular plate 47 Annular plate 47, itself, is secured within the valve body 28 by a snap ring 48 which is anchored within a valve body recess 49. With annular plate 47 locked in position by snap ring 48, the spring 46 is maintained so as to exert a desired force transmitted through the piston 41 and acting on the valve member 31 to resist valve closing or port closing movement of this member 31. Generally, the spring 46 will be preloaded or precompressed by the installed plate 47. In this manner, the member 31 is yieldably biased to an open position under a load which will be offset by the predetermined loading on the coupling bar 6 necessary` to generate sufficient pressure within the zone 10b to effect valve opening.

As illustrated in FIGURES 5 and 7, annular plate 47 includes a central aperture 50 through which the open lower end of the member 31 slidably and telescopingly projects. A plurality of ports 51 in the plate 47 provides limited fluid communication between the reservoir 11 and an annular zone 52 within the body 28 communicating with the piston 41. In this connection, it will Vbe appreciated that the entire valve member 27 is immersed in the hydraulic fluid occupying the reservoir 11 and cylinder cavity 10 and thus will also occupy the space 52. Thus, piston 41, in cooperation with ports 51, will provide a dashpot or movement impedance effect on member 31, tending to prevent valve chattering As fluid is discharged through the port 26 in response to draft movement of the cylinder 3, this fluid will be first radially impinged on the fluid reaction surface 34. This fluid will then be deflected laterally to flow into an annular space 53 defined by wall means 54 of socket 30. This relatively enlarged annular zone 53 provides communication between the port 26 and the ports 35 of the valve member 31, when the valve member 31 is in an open port position as shown in FIGURE 4 and FIGURE 5.

Fluid, after having been deflected by the reaction surface 34 into the annular zone 53 defined by wall 54, will flow through the restricting ports 35 into the valve member passage 37. These flow restricting orifices or ports 35 will produce a pressure drop between fluid in the space 53 and fluid in the passage 37 so as to tend to produce a valve closing pressure differential force acting on the valve head 33.

As 1a result of this pressure differential, probably augmented by the force generated by the impingement of fluid on the reaction surface 34, a valve closing force will be exerted on the valve member 31, which of course is normally held open by the biasing spring 46. When train action draft force is imposed on the coupling bar 6 to produce a pressurized flow through vent 26, impnging on the surface 34 and passing through the ports 35, this flow will create sufficient force acting on the valve 31 so as to overcome the biasing effect on the spring 46. The valve member 31 will then move radially outwardly of the cylinder 3 and close the port 26. However, when relatively low force is imposed on the cylinder 3 or the coupling bar 6, such as the force imposed by restoring mechanism 18, a flow of velocity and pressure insufficient to effect the closing of the valve 27 will take place through the port 26. In practice, it has been found that the spring 46 should be adjusted to enable the valve 27 to close in response to a total imposition of draft force on housing 2 on the order of about 21,000 pounds, with about 7,600 pounds of this force being supplied 4by restoring mechanism 18. In other words, valve 27 will close in response to a train action draft force of about 13,000 pounds.

As will be appreciated, the valve member 27 is coupled to the cylinder 3 so as to be sealingly engaged with the socket 30.v A conventional lock washer 55 may be inter posed between the valve body 28 and the cylinder wall 3 to securely anchor the valve member 27 on the outer periphery of the cylinder 3.

SUMMARY OF MAJOR ADVANTAGES AND SCOPE OF INVENTION In discussing the significant advantages attributable to the valve mechanism of this invention, it is appropriate to first review the overall characteristics of the draft gear in which the valve is incorporated. These characteristics may best be depicted by reference to the performance of the gear on adverse rail beds such as that shown in profile in FIGURE 1.

FIGURE 1 illustrates the profile of a portion of a rail bed on a Canadian track extending between Garneau and Riviere aPiere, Quebec. The maximum grade on this track is about 3.6 which is unusually steep. In addition to the grade problem, the track undulates severely in profile so as to tend to produce conditions uniquely conducive to train action events.

FIGURE 1 illustrates a track profile with vertical guide markers being provided at one mile increments. Track slope in degrees has been noted at varying points along this profile. The lowest point on this profile, i.e., point X, has an elevation above sea level of about 520 feet. The highest point Y on this profile has an elevation of about 632 feet above sea level. In the vicinity of the twomile marker in the FIGURE'I profile, a train moving from left to right moves down an incline at about 2.8 and then abruptly up an incline of 2.3 and then subsequently abruptly down another incline of about 1.9". As will be apparent, by reference to FIGURE 1, these changes in inclination are closely spaced and fairly well typify the grade profile. Thus, in moving down the 28 slope and approaching the two-mile marker, the cars of the train will tend 'to converge so as to produce run-in train action. Then abruptly, after clearing the two mile marker, and While moving up the 2.3 slope, the cars will tend to separate so as to produce train action run-out events.

Where conventional, frictional type, draft gear has been employed, this 40 mile length of track between Garneau and Riviere aPiere, has produced extraordinary severe train action. The upper Section A of FIGURE 2 provides a graphical indication of a representative number of run-in and run-out train events, and the severity of these train events, which were encountered with standard friction type draft gear traversing this track.

FIGURE 2 dramatically illustrates the extent t0 which the previously described draft gear reduces over all severity and number of train action events. Section B of the chart shown in FIGURE 2 illustrates run-in and runout events, both by number and magnitude, for the same track with a similar train, but where train action Was governed by cushioning devices generallyconstructed in accordance with the present invention. The essential similarities in the trains involved in compiling Sections A and B of FIGURE 2, and the inclusion of the draft gear used in compiling Section B of the chart of the exponential port means 23, the supplemental port means 24, a valved port 26, and a restricted port 25, are believed to provide a valid basis for evaluating the improved train action control afforded by this invention. In this connection, it should be noted that the tests which produced the data 10 for Section B of FIGURE 2 were performed where the vent 25 was less advantageously disposed as an axial orifice in the valve head 34.

In comparing Section B with Section A of FIGURE 2, it will be noted that run-outs were reduced from 29 to 8 while run-in events were reduced from 17 to l2. The magnitude of run-out forces were substantially reduced, with the number of run-in events at higher run-in force being reduced. In this connection, it should be noted that the single run-in event which occurred with a run-in force between 200,000 and 300,000 pounds is believed to have resulted from train braking and thus probably does not provide valid data for comparison purposes.

A principal advantage of this invention resides in the ability of the improved valve mechanism to effectively control or minimize train action run-out events while allowing for an adequate rate of coupling restoration under free air conditions, i.e., while significant force is not being imposed on a coupling bar by an adjacent railway car.

Another principal advantage of the invention resides in the inherently compact structure of the valve mechanism, resulting from its mutually telescoped components, which yield both structural ruggedness and a unique conservation of space.

A particularly significant advantage of the invention involves the reliable and responsive operating characteristics of the valve due, to a large degree, to the utilization of valve ports which provide a valve closing differential force.

Another important advantage attributable to the improved valve mechanism entails the utilization of the movement damping, dashpot piston which serves to minimize valve chattering tendencies.

The impingement of the outflow of fluid from the draft zone of the cylinder upon the valve fiuid reaction surface is also advantageous. This utilizes the outflow of fluid during the extension of a coupling bar to impose a valve closing force on the valve as a fiuid velocity phenomenon.

In being submerged in the hydraulic oi l of the reservoir 1, valve 27 is both continuously lubricated and cooled. This factor, coupled with the basic ruggedness of the valve 27, should tend to virtually eliminate or highly minimize maintenance and replacement problems.

It is also significant to note that this improved valve structure may be easily incorporated in effective shock absorbing mechanisms such as those disclosed in the aforementioned Blake patents and Seay patent without requiring any significant structural alterations of the basic components of these devices.

Those familiar with the disclosure of this invention will at once recognize that its scope is not limited to the port type venting system described, or to the particular piston and cylinder arrangements illustrated. As was noted in the aforesaid Seay patent, limited deviations with respect to optimum port positioning is tolerable within the spirit of the invention.

Thus, those skilled in the art may recognize additions, deletions, substitutions, modifications, or other changes which would fall within the scope of the invention.

I claim:

1. In railway draft gear, including a tiuid shock absorbing assembly comprising cylinder means and piston means, with the piston means being connected with one of a coupling portion and body portion of a railway car and the cylinder means being connected with the other of said coupling and body portions, valve means for regulating an outfiow of liuid from a piston biasing zone of said assembly, the improvement in valve means comprising:

a valve body;

a movable Valve member;

a valve seat carried by said valve body;

a fluid reaction surface on said movable valve member upon which fluid outflow from said assembly is adapted to impinge;

port means carried by said movable valve member and operable in response to a uid iiow therethrough emanating from said piston biasing zone of said assembly to create a pressure differential across said movable valve member tending to move said valve member into valve closing engagement with said seat; and

resilient means biasing said valve member away from said valve seat so as to yieldably position said valve member with the ports thereof open;

dashpot means operable to retard movement of said valve member toward said valve seat so as to close said ports;

first wall means defining an axial flow path leading axially from said piston biasing zone toward said uid reaction surface and adapted to deiine an axial iiow having a cross-sectional area substantially less than the cross-sectional area of said movable valve; and

second wall means defining an annular chamber providing uid communication between said axial iiow path and the port means of said movable valve member.

2. In railway draft gear, including a fluid shock absorbing assembly comprising cylinder means and piston means, with the piston means being connected with one of a coupling portion and body portion of a railway car and the cylinder means being connected with the other of said coupling and body portions, valve means for regulating an outtiow of uid from a piston biasing zone of said assembly, the improvement in valve means comprising:

a valve body;

a movable valve member;

a valve seat carried by said valve body;

a iiuid reaction surface on said movable valve member upon which fiuid outow from said assembly is adapted to impinge;

port means carried by said movable valve member and operable in response to a uid flow therethrough emanating from said piston biasing zone of said assembly to create a pressure differential across said movable valve member tending to move said valve member into valve closing engagement with said seat;

iirst wall means defining an axial ow path leading axially from said piston biasing zone toward said iiuid reaction surface and adapted to dene an axial flow having a cross-sectional area substantially less than the cross-sectional area of said movable valve;

second wall means defining an annular chamber providing uid communication between said axial ow path and the port means of said movable valve;

rst abutment means carried by said valve member;

second abutment means carried by said valve body and operable to engage said iirst abutment means to limit valve closing movement of said valve member;

annular piston means slidably mounted within said body, with said valve member extending axially through said annular piston means;

third abutment means carried by said valve member;

coil spring means contained within said valve body, engaging said annular piston means and biasing said annular piston means toward the port means of said valve member and into engagement with said third abutment means;

annular plate means iixedly mounted within said valve body and providing fourth abutment means for engaging said coil spring means and holding said coil spring means within said body and in engagement with said annular piston means;

said coil spring means exerting a predetermined biasing force on said annular piston means, with said valve member telescopingly passing through a centrally apertured portion of said annular plate means;

port means in said annular plate means providing restricted uid communication between the exterior of said valvebody and an annular zone within said valve body having longitudinally spaced ends defined by said annular piston means and said annular plate means and having inner and outer side walls defined respectively by the outer peripheral portion of said valve member and an inner peripheral portion of said valve body; and

means defining a uid reservoir on the exterior of said cylinder means of said shock absorbing assembly substantially surrounding said valve body.

References Cited UNITED STATES PATENTS 2,161,811 6/1939 Grebe. 3,207,324 9/ 1965 Blake 213--8 3,301,410 1/1967 Seay 213-43 DRAYTON E. HOFFMAN, Primary Examiner U.S. Cl. X.R. 

